1. Field of the Invention
The present invention relates to an air-filling cushioning material for packing an article to be protected without damaging.
2. Description of Background Art
Conventionally, an air-filling cushioning material manufactured by overlapping soft resin sheets and forming a portion having a space where air can be filled between the sheets has been widely used. By bringing the whole or part of the article to be protected in contact with the air-filling portion of the air-filling cushioning material, the article can be protected against an external shock.
As an example of such an air-filling cushioning material as described above, an air-filling cushioning material by the applicant of the present application as disclosed in Japanese Published Unexamined Patent Application No. H07-285581 (referred as patent literature 1 later) has been proposed. According thereto, cells of air-filling portions are formed in a sectioned manner by adhering airtight soft resin sheets. An article brought in contact with the air-filling cushioning material is protected by a cushioning effect of the cells where air is filled.
Herein, this air-filling cushioning material is structured so that, compared to one side thereof, the other side inflates larger when air is filled in the cells. Since the surface of the one side of the air-filling cushioning material can be maintained nearly flat, this is an advantage when the same is used for an envelop or the like with a cushioning effect.
In this air-filling cushioning material, a flat sheet is used for one of the overlapped sheets, and the other sheet is stuck to the first sheet in a slackened state, whereby cells are formed. Concretely, the other sheet 101b is tucked or pleated as shown in FIG. 9.
At an end portion S of the air-filling cushioning material, this tucked part in a tucked state and one sheet 101a and the other sheet 101b are integrally adhered. So, the end portions of the cells 102 do not inflate well, remaining in a tucked state even when air is filled in the cells 102.
Also, in a case where the air-filling cushioning material formed as in the above is folded so as to cross the cells 102 into a three-dimensional configuration such as an envelop, if the fold is formed by simple folding, the crease of the fold may not keep its shape due to the air filled in the cells 102.
In some cases, heat-sealing, or forming a spot seal in other words, is partially applied in the cells 102. When a resin layer without heat-sealabiltiy is used for the outermost layer of multiple resin layers in the other sheet 101b, a spot seal can be formed in the spot shown as P1 in the drawing. In the tucked area, however, a spot seal cannot be formed in the spot P2 where a resin layer without heat-sealability is tucked and overlapped.